Percentage Calculator
Solve every common percentage problem — increase, decrease and of.
What do you want to work out?
Find a percentage of a number.
Result
30
Step by step
- 115% of 200 = (15 ÷ 100) × 200
- 2= 0.15 × 200
- 3= 30
About the Percentage Calculator
Percentages turn up everywhere — discounts, tips, tax, test scores, interest and statistics — but the wording trips people up because “percent” questions come in several shapes. This calculator handles the four most common ones in one place, and shows the working for each so the method is clear, not just the answer.
Use “Percent of” to find a slice of a number (what is 15% of 200?). Use “Is what %” to express one number as a percentage of another (50 is what percent of 200?). Use “Change” to measure the percentage increase or decrease between a starting and ending value — handy for price changes, growth or weight loss. And use “Adjust” to add or take a percentage off a number, which is exactly what a discount or a markup does.
Every percentage is really just a fraction of 100: 25% means 25 per hundred, or 0.25. Once you see which of the four questions you're asking, the arithmetic is straightforward — and the step-by-step panel walks through it each time.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 200 is (15 ÷ 100) × 200 = 0.15 × 200 = 30. The “Percent of” mode does this for you and shows each step.
How do I work out percentage increase or decrease?
Subtract the starting value from the ending value, divide by the starting value, then multiply by 100. Going from 200 to 250 is ((250 − 200) ÷ 200) × 100 = 25%, an increase. A negative result means a decrease. Use the “Change” mode for this.
What's the difference between “percent of” and “percentage change”?
“Percent of” finds a portion of a single number (15% of 200). “Percentage change” compares two numbers to see how much one grew or shrank relative to the other. They answer different questions, so the calculator keeps them as separate modes.
How do I add or subtract a percentage, like a discount or tax?
Use the “Adjust” mode. To take 20% off 50, it works out 20% of 50 (which is 10) and subtracts it, giving 40. To add tax, switch the direction to Increase. This is the same math shops use for discounts and markups.
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